In 1975 it was reported by Dr. S. K. Ries, in the Michigan Agricultural Experimental Station Journal Article, No. 7431, that coarsely chopped alfalfa hay when applied to the soil as a band adjacent to a crop row could improve plant growth. This phenomenon was mentioned with respect to lettuce, rice, cucumbers, tomatoes, cauliflower, and field corn. In an article that appeared in Science, Mar. 25, 1977, Volume 195, pages 1339 through 1341, Ries and his coworkers reported the isolation of triacontanol as the active growth agent that had been present in the earlier alfalfa work and laboratory scale foliar application to field corn of a solution containing 0.01 milligram per liter up to 1.00 milligram of triacontanol per liter was reported.
Biological activity of 1-triacontanol has been shown to be extremely sensitive to its method of synthesis. This observation is believed to be a function of the amount and type of impurities derived from the synthetic method, i.e. different methods produce different amounts and types of impurities, some of which are potent inhibitors. (See Jones J., Wert F. V., Ries, S. K., Planta 144: 277-292 (1979).
U.S. Pat. No. 4,150,970, S. K. Reis and C. C. Sweeley, discloses and claims the use of 1-triacontanol as a growth regulator for plants. Specifically claimed is a method for stimulating the growth of a plant selected from rice, wheat, corn tomatoes or barley, by applying thereto an effective amount of 1-triacontanol. The means of application can be a foliar spray, a soil drench, a side dressing or as part of an insecticide or fertilizer application.
U.S. Pat. No. 4,167,641 describes a process for the preparation of triacontanol.
U.S. Pat. No. 4,367,346, issued Jan. 4, 1983 by one of the present inventors discloses a new method for the synthesis of 1-triacontanol.
U.S. Pat. No. 4,230,485 discloses a method for the treatment of field corn with triacontanol. This patent teaches that the stage of plant maturity is the key to the attainment of increased yields in field corn. Foliar applied rates from about 2 milligrams to about 56 milligrams per acre were found to be equally effective. The dissolution of triacontanol in chloroform was found to be an effective procedure but acetone was found to be a more effective solvent. Other solvents such as the amyl alcohols were speculated to be equally or more effective.
U.S. Pat. No. 4,299,618 discloses that soybean crop yield can be increased by the foliar application of small amounts of trialkyl 2,4-dichlorobenzylammonium chlorides during certain stages of growth. Application to northern intermediate varieties at a rate of about 0.25 to 0.5 pounds (0.11 to 0.23 Kgs) per acre during the 5-8 trifoliate leaf stage was disclosed. Application to the southern varieties at a rate of about 0.5 to 0.75 pounds (0.23 to 0.34 Kgs.) per acre during the 10 to 11 trifoliate leaf stage was found to be satisfactory.
Numerous investigators have attempted to increase the yield of soybeans through application of 1-triacontanol. At present the yield increases in soybeans have been either nonexistent or erratic. As soybean production is an important part of the American agricultural industry, it is evident that a method which can substantially increase the yield of soybeans through use of 1-triacontanol would be highly desirable. No reference has been found that is concerned with increasing, specifically soybean crop yield. Most significantly, no reference teaches the optimum times, rates of application, timing of application, number of applications and attendant spray solution preparation that can effectively and dramatically increase the yield of soybeans.